${2 \div 0.8 = {?}}$
Explanation: $ {2 \div 0.8 = 2 \div \dfrac{8}{10}} $ $ {\phantom{2 \div 0.8} = 2 \div \dfrac{4}{5}} $ Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. $ {2 \div \dfrac{4}{5} = 2 \times \dfrac{5}{4}} $ $ {\phantom{2 \div \dfrac{4}{5}} = \dfrac{2 \times 5}{4}} $ $ {\phantom{2 \div \dfrac{4}{5}} = \dfrac{10}{4}} $ $ {\phantom{2 \div \dfrac{4}{5}} = 2.5} $